Electrical apparatus



A. w. LUNDSTROM ELECTRICAL APPARATUS Inventor Axel W. Lundstr 0m,

y I His JTttovneg.

March 18 1924.

Patented Mar. 18, 1924.

UNITED STATES PATENT OFFICE.

AXEL W. LUNDSTROM, OF NEW YORK, N. Y., ASSIGNOR T GENERAL ELECTRIC COM PANY, A CORPORATION OF NEVT YORK. 4

ELECTRICAL APPARATUS.

Application filed April 9,

To all whom. it may concern:

Be it known that I, AXEL W. LUNnsTRoM, a citizen of the United States, residin at New York, in the county of New ork, State of New York, have invented certain new and useful Improvements in Electrical Apparatus, of which the following is a specification. v

My invention relates to casings for enclos-*' ing electrical apparatus and which must be so arranged as to give ready access to the devices contained within them. Such casings are commonly used as safety devices in connection with small electrical apparatus such as fuses, small switches, etc., to prevent people coming into contact with live electrical parts. The object of my invention is to provide for cooperation between a latch on the door of the casing and a switch, and preferably in addition cooperation with the door itself,- whereby access may be had to the interior of the casing only when certain parts are in certain positions, as when the switch is open and the contents of the easing or parts thereof thereby are deenergized and safe to .handle, and preferably where by parts of the devices may, through the latch, be positively locked in certain positions. My invention can best be described and distinguished by a detailed description of an embodiment thereof.

In the accompanyingdrawing-and following description I have illustrated and described in some detail the best embodiment of my invention of which I am now aware. Fig. 1 is a plan view of the important parts of the apparatus embodyin my invention, certain parts of the latch an related mechanism being shown in dotted lines. F ig. 2 is a sectional elevation of the device embodying my invention. Figs. 3 and t are similar views of the same apparatus, elements of the invention being in different positions. Fig. 5 is a larger and sectional view of the means for operating the latch illustrated in the preceding figures.

The casing 6 is provided with a door 7 hinged at 8 and opening away from the easing as shown particularly in Fig. 4. This easing contains a fuse or setof fuses 9 in the line or lines controlled by the switch represented at 10. The door 7 gives access to the fuse or fuses 9. A barrier 13 divides the casing into two portions and to an ex tent separates the switch from the part 1919. Serial no. 288,800.

of the chamber containing the fuse or fuses. The latch for the door '7 comprises two parts 15 and 16. The part 16 is carried by guides 17 on the fixed part 18 of the cover of the casing 6 and is carried by these guides in such a way that the part 16 may slide to the right and to the left as shown in the figures. The part 15 of the latch is bent down at its outer end and at its other end is loosely connected to the part 16 in such a manner that it may turn angularly thereon in the plane of the drawing of Fig. 1 to a small extent; and also so that it may turn angularly in the plane of the drawing of Figs. 2, 3 and 4 as is particularly shown by a comparison of Figs. 3 and 4. The purposes of these combined movements of the, part 15 will appear later; in general they allow the door to be unlatched and to be opened on its hinges 8 as is shown in Fig. 4: particularly. It will be noted that the connection between parts 15 and 16 is so disposed that this connection stands near the hinges 8 when the latch is in. door unlatched position, that is, is moved to its extreme left hand position as shown in Fig. 4:. The latch is moved by an angularly movable disc 20 which is fixed to the shaft 21 (see Fig. 5) at its squared upper end;' the disc 20 and shaft 21 are carried by the ylindrical member 22 which surrounds the shaft 21 andis fixed to the cover 7. The upper end of this cylindrical member 22 extends outwardly into the shape of a fixed disc 23 immediately below the movable disc 20 and the two discs are rovided with cooperating recesses or ho es as later described. The shaft 21 extends through the cover 7 as a pears from igs. 2 and 5 and its lower squared end carries an arm 25 pivoted to the latch part 15 as shown particularly in Figs. 1, 2 and 5. It will be seen particularly from these figures that as the disc 20 is rotated the shaft 21 and arm 25 will move the latch '15 slightly angularly in the plane of the drawing of Fig. 1 and at the same time move the latch parts 15 and 16 to the ri ht or to the left of all the figures, thereby latching or unlatching the door.' Particularly for most securely latching the door 7 the latch part 15 is adapted in its extreme right hand position to project under the L-shaped or angle member 26 fixed to the right hand wall of the casing 6. It will be observed that this angle member 26 projects some distance to the left in Fig. 2,

and is also of some considerable length as shown in Fig. 1. The purpose of the extreme projection of the member 26 to the left and its considerable length is to allow some movement of the part 15 angularly and to the left without unlatching the door by disengagement of the part 15 from the member 26. The purpose of this feature will be explained hereafter. The outer surface of the door 7 is provided with a vertical seg ment 30 projecting beyond the left hand edge of the door 7 and into a slot 31 in the adjacent edge of the wall 18. This segment 30 is so disposed that as the door 7 is opened this segment 30 projects downwardly through the slot 31 into the interior of the casing 6 (as shown in Fig. 4), while this segment is above the lower surfaces of the wall 18 and the door 7, and also above the latch part 16, while the door 7 is in its closed position (see Figs. 2 and 3). The latch part 16 is provided with a slot 32 so located as to stand immediately below the end of the segment 30 projecting through,

the slot 31 when the latch is moved to its extreme left hand position (Fig. 4), but in all other positions of the latch some portion of the part 16 stands below the segment 30 (Figs. 2 and 3).

Immediately to the left of the latch part 16 stands the switch 10. The stationary contacts 38 and 39 of this switch are car ried by the same base 40 which carries the fuse or fuses 9 and the attaching clips. The movable bridging member-41 of the switch bridges the contacts 38 and 39 in the closed position of the switch (Fig. 2) and completes the circuit from the line connector 42 through contact 38, bridging member 41, contact 39, and fuse 9, to line connector 43. Supplemental movable contacts or projecting pieces 44 are provided at the ends of the bridging member 41 to provide the surfaces of the switch at which the circuit is initially made and initially broken in a manner well understood. It will be understood that the switch I have illustrated may have only one set of contacts 38 and 39 and only one bridging contact 41, or the drawings (Figs. 2, 3 and 4) may represent apparatus in which there are a plurality of stationary contacts 38 disposed one behind the other, and similarly a plurality of contacts 39, bridging contacts 41, and fuses 9 and pairs of attaching clips respectively disposed behind those shown. Indeed, s eaking broadly, the exact nature of the e ectrical devices contained in the casing is immaterial to my invention. For simplicity, I refer herein mostly to only one contact 38, one contact 39, one bridging member 41, and one fuse 9 and pair of attaching clips.

Projecting from below the bridging member 41 is a vertical rod 47 which passes freely through the base 40 as the bridging member is raised and lowered. A spring 48 surrounds and is directed by the rod 47 and is so tensioned as to tend to open the switch by moving the member 41. The operating means for the switch consists of the switch lever 49, one end of this lever has the form of a handle and projects through the wall 18 while the other end is pivoted at and has the general shape of an extended segment. The segment of the switch lever 49 is in the path of movement of the latch part 16, and when this part 16 is in its extreme right hand position it is at mostonly just out of engagement with the edge of the segment. Also carried on the pivot 50 is one arm 51 of the switch operating and looking toggle the other arm 52 of this toggle connects the arm 51 to the bridging member 41 as shown. )Vhen this toggle 5152 is in extended position (Fig. 2) the switch is held closed thereby against the tension of the spring 48. \Vhen this tog'gle is broken by displacing the juncture of 51 and 52 to the left, the switch is moved to its open position (Fig. 3) by the spring 48. The segment of the switch lever 49 carries a pin 55 in the path of movement of the toggle arm 51; this pin is so disposed on the segment of the lever 49 that when the handle is in its extreme left hand position (Fig. 2) the pin 55 just engages with the arm 51 in its vertical position shown. The switch lever segment also carries a pin 56 which is so locatedthat when the switch lever 49 is moved from its left hand position (Fig. 2) toward the right, and just before it reaches its extreme right hand position, the pin 56 engages with the right hand or upper end of the arm 51 and further movement of the switch lever de )resses the right hand end of the arm 51, t us breaking the toggle and allowing the spring 48 to open the switch with a quick movement of brid ing contact 41 to its upper position. It will e observed that the slot in the wall 18 through which the switch lever 49 projects limits the movement of the switch lever 49 both to the right and to the left. A s ring tends to hold the lever in its position to the left but the'tension of this spring is overcome by the spring 48 when the toggle 5152 is broken. It will also be noticed that the right hand end of the toggle 51 is in the shape of the segment and that the radius of this segment is slightly shorter than the radius of the segment of the switch arm 49; the urpose of this segment and the reason why its radius is shorter than the radius of the segment of arm 49 will later appear.

The segment of the switch arm 49 is provided with a slot 59 as shown, this slot being so disposed as to stand exactly opposite the left hand end of the latch .part 16 when ment of the switch lever 49. Accordingly the switch lever 49 may be moved freely to the right or to the left and the switch thereby o ened and closed. The switch may be opene by movement of the lever 49 to the right from its position in Fig. 2, until the in 56 engages and moves arm 51, thus breaiing the toggle and allowing spring 48 to open the switch; or it may be closed by movement of the lever 49 ,to its left hand position, the pin engaging the other end of arm 51 and carrying the toggle 51-52 to its extended position (Fig. 2). So long as the switch is closed (Fig. 2) it is impossible to unlatch the door 7 since any rotation of the hand disc 20 to this end only results in retracting the latch slightly to the left until the part 16 engages the segment of the switch arm 49; further. movement of the latch to the left is prevented thereby. Accordingly, so long as the switch is closed it is impossible to unlatch and hence to open the door 7. If now the switch is opened by moving the switch lever 49 to its extreme right hand position (Fig. 3), the slot 59 is thereb disposed opposite the part 16 and one 0 two retracting movements may be made. The hand disc may be partly rotated to move the latch parts 15 and 16 a short or intermediate distance to the left so that the part 16 enters the slot 59. In such a position that the disc 20 may be so far rotated that the latch is moved to its extreme left hand 'osition. Vith this movement the part 16 is moved completely into the slot 59 (Fig. 4), the slot 32 in the part 16 is brought below the segment 30 and the art 15 is car- 'ried compl'etel from under t e angle mem:

ber 26. In t is position of the latch the switchis as before held in its open position but at the same time the door 7 ma be opened for the latch 15 is in its unlatc ing position and the slot 32 provides for the passage of the segment 30 through-the part 16. When the door is in its open" osition' the other parts and elements have t e positions shown in Fig. 4. It will be seen, therefore, that when the door 7 is closed the switch 10 may be opened and closed freely; that-with the door still latched closed the switch may be held in its open position; and that only when the switch is held in its open position can the door 7 be opened and access gained to the electrical devices 9. Providing, therefore, that the line terminal or terminals 42 are those connected to the source of supply of electrical energy, the terminal or terminals 43 being connected to the load, then access may be had to the electrical devices 9 only when these 1 devices are disconnected from the electrical source and hence only when these devices may be touched and handled with safety. So long as the latch stands to any extent to the left of itsextrcme right hand or advanced position, the switch is held' open. The segment 30 of the door 7 prevents the movement of the latch to the right while the door 7 stands open. As before pointed out as long as the door 7 stands sufficiently open to allow the movement of the latch part. 15 to the right without passing under the. angle member 26, the segment 30 stands within the slot 32 of the part 16. Accordingly in order to move the latch to the right, it is necessary to completely close the door for only in that position of the door will the part 16 pass the segment 30. Accordingly it will be seen further that so long as the door 7 is not completel closed, it is impossible to close the swltc 10, and that the latch part 15 must be ositioned to the left in order that its bent own end may clear the angle member 26 in closing. I

In some instances it is desirable to provide for positively locking various 0 purpose I provide the stationary disc 23 with assages 60, 61 and 62 and I also provide t e hand disc 20 with a passage 63 to cooperate with the passages 60, 61 and 62. These four passages are so arranged that assage 63 stands above passage 60 when the atch is in its extreme right hand position; and passage 63 stands a ove 61 when the latch is in its middle position, that is, with the part 16 just within the slot 59; and 63 the device in its possible positions. For this these three positions. Hence, it is that the 4 device may be positively locked with the door 7 in its closed position, the switch being movable to-its open and closed positions at will; may be locked with the door in its closed position and the switch in its open osition; and may be locked with the door 1n its open position and theswitch in its open position. It will be observed, however,

iso

that the switch cannot be locked in its closed position. A second set of openings like 63 may be provided in the discs 20 and '23 as shown in Fig. 1, if desired, and as indicated in Fig. 1, thereby the device may be made subject to two independent locks and to two independent keys.

The segment shape of the right hand end o1 the toggle arm 51 provides against the possible movement of the latch part 16 below this end of this toggle arm 51 and hence against all possibilities of the part 16 preventing the opening of the switch. The radius of the segment of this arm 51 is slightly shorter than the radius of the segment of the switch lever 49 in order that the part 16 may not bear against the arm 51'and thus possibly increase the friction to be overcome by the spring 48 in opening the switch. For example, just prior to the opening of the switch the hand disc 20 may be 'rotated until the part 16 engages with the segment of the switch lever 49. It now the switch is to be opened the only restraint by the left hand end of the part 16 is restraint of the movement of the switch lever 49, and since this switch lever is to be manually operated, this small restraint is without effect. Once the pin 56 has started the movement of the arm 51, the switch opens just as easily and freely as though the part 16 were in its extreme right hand position for by' reason of the shorter radius of the segment of the arm 51 this arm is completely out of engagement with the part 16 and hence not restrained thereby.

While T have illustrated and described the best embodiment of my invention of which I am now aware, it will be understood that this embodiment is merely illustrative of my invention and that .my invention is not limited thereto but is set forth in the following claims.

lVhat I claim as new and desire to'secure by Letters Patent of the United States, is

1. The combination of an electrical device, a manually operated switch, a case provided with a door enclosing said device, and a latch manually operated entirely independently of the operation of said switch, for latching said door in closed position, a part moving with said switch being disposed inthe path of travel of a part moving with said latch when the switch is in closed position to prevent the unlatching of the door until the switch has previously been separately and independently opened, and being removed from saidpath when the switch is in open position.

2. The combination of an electrical device, an enclosing case for said device, a

switch operating entirely independently and each incapable of effecting operation of the other, and a part movable with said latch into the path of travel of a part moving with said switch when said latch is retracted to prevent movement of said switch so long as the door is open or unlatched.

3. The combination of an electrical device, a manually operated switch, a case provided with a door enclosing said device, a latch manually operated entirely independently ot' the operation of said switch for latching said door in closed position, a art moving with said latch being disposed in the path of travel of a part moving with said switch when the latch is in retracted position to prevent the movement of the switch to its closed position so long as the door is unlatched and being removed from said path when the latch is in advanced position, and means standing in the path of travel of a part. moving with said latch so long as said door is open to prevent the advancement of the latch when the door is open.

t. The combination of an electrical device, a switch, a case provided with a door closing said device, a separately operable latch for latching said door in closed position, a part moving with said latch being disposed in the path of travel of a. part moving with said switch both when the latch is in retracted position and when the.latch is in intermediate position, to prevent the movement of the switch to its closed position so long as the latch is in either of said positions, and the first mentioned part being removed from said path when the latch is in advanced position, and means standing in the path of travel of the part moving with said latch so long as said door is open to prevent the movement of the said part from its switch movement preventing position when the door is open.

5. The combination of an electrical device, a switch, a case provided with a' door enclosing said device, and a latch movably mounted on said door for latching it in closed position, said switch being provided with a segment operating therewith in the path of movement of a part moving with said latch and provided with a notch to receive said part when the switch is in open position.

6. The combination of an electrical device, a switch, a case provided with a door enclosing said device, a latch for latching said door in closed position, said switch and latch being provided with means for preventing the movement of the latch to unlatching position until the switch has previously been separately opened, and for preventing the closing 0 the switch when the latch is in unlatching position, and a segment carried by said door standing in the path of travel of a part movable with said latch so long as the door is open to prevent the movement of the latch to latching position when the door is open.

7. The combination of an electrical device, a' switch, a case provided with a door, enclosing said device, a latch for latching said door in closed position, parts movable with said switch and said latch and cooperating to prevent the unlatching of the door when the switch is closed and the closing of the switch when the dooris unlatched, a hand member movable angularly with the movement of the latch, and a stationary member arranged coaxially of said hand member and both of said members being provided with means for positively locking the same together in the latched and linlatched positions of the latch. v

8. The combination of an electrical device, a switch, a case provided with a doorenclosing said device, a latch for latching said door in closed position, parts movable with said switch and said latch and cooperating to prevent the unlatching of the door when the switch is closed and the closing of the switch when the door is unlatched, an angularly movable hand member for operating said latch, a stationary member arranged I coaxially of said hand member and means for positively locking said members in the latched and unlatched positions of the latch.

9. The combination of an electrical device, a switch, acase provided with a door-enclosing said device, a latch for latching said door in closed position, parts movable with said switch and said latch and said door and cooperating to prevent the unlatching of the door when the switch is closed, the closing of the'switch in one latched position and also the unlatched position of the latch, and the movement of the latch to latching position when the door is open,

' means moving angularly with the movement of the latch, and means for positively locking said angularly moving member in the said two latched positions of the latch and in its unlatched position. 7

In witness whereof, I have hereunto set my'hand this 2d day of April, 1919.

AXEL W. LUNDSTROM. 

